\begin{tikzpicture}[>=Stealth, scale=0.8]
    \draw (0, 0) rectangle (6, 1);
    \draw (3, 0) -- (3, 1);
    \node at (1.5, 1.3) {第 $1$ 位};
    \node at (4.5, 1.3) {第 $2$ 位};
    \draw [<-] (1.5, -0.1) -- (1.5, -0.5) node[below] {$n$};
    \draw [<-] (4.5, -0.1) -- (4.5,  -0.5) node[below] {$n - 1$};
\end{tikzpicture}
